Thursday, April 28, 2016

MEAT AND AGEING: CUTTING THROUGH THE CONFUSION


A new study published in the journal, Ageing, has claimed that eating meat frequently could be linked with an increase in blood phosphate levels that contributes to faster ageing of body cells. Here, we unpick the evidence.

The study measured blood phosphate levels in 666 adults recruited from Glasgow. Participants estimated their own dietary intakes by filling out a 21-category food frequency questionnaire which asked whether they tended to eat certain foods daily, weekly or monthly. No portion sizes were recorded.

The researchers then correlated blood phosphate levels with markers of biological ageing including telomere length (a measure of cell ageing), inflammation, and DNA hypomethylation (a marker of DNA abnormalities). Higher phosphate levels in the blood were statistically associated with worse cell ageing.

Commenting on the study, Dr Carrie Ruxton, from the Meat Advisory Panel notes:

“The conclusion of this study – that eating red meat is somehow to blame for faster ageing – bears no relation to the evidence the researchers actually collected. I am amazed that Glasgow University should be willing to publicise this illogical piece of work.

“Dietary phosphate comes from a wide variety of sources, including meats, fish, eggs, dairy products and vegetables, as noted by the authors themselves in the paper.
Therefore, using a cross-sectional ‘snapshot’ of diet and blood samples as was the case in this study, it is impossible to say which individual dietary component was responsible for people’s raised blood phosphate levels.

“The dietary assessment only asked participants to record how often they ate a food – no data were collected on the amounts eaten. Again, this hampers any chance of linking diet with phosphate levels. To do this, you would need a controlled clinical trial which varied the amounts of phosphate-containing foods in the diet.

“Looking at the authors’ theory that a higher meat intake in lower socio-economic groups contributed to faster ageing, national diet data actually show lower or similar intakes of red meat in less well-off groups of people. The National Diet and Nutrition Survey which has data on more than 6000 individuals reported that men in the two lowest socio-economic groups ate 84-85g of red and processed meat daily, while men in the two highest socio-economic groups ate 83-93g daily. For women the differences were 53-57g daily in the lowest two groups and 56-59g in the highest two groups. This means that the authors of the paper are wrong about differences in red meat intakes across socio-economic groupings.

“Randomised controlled trials which vary lean red meat consumption have not found detrimental effects on markers of health. For example, a 4-month study in elderly women which delivered a red meat intake of 160g daily on 6 days of the week found a significant reduction in inflammation.

“In conclusion, all this study can say is that higher blood phosphate levels are linked with faster cell ageing, and that red meat and blood phosphate are statistically correlated. It tells us nothing about the cause of high phosphate levels, or the cause of faster ageing. The elementary theory that red meat is to blame is simply speculation and is not based on solid evidence.

"Red meat is a valuable source of iron, selenium, B vitamins and vitamin D – all of which would be expected to support normal health.”

-ENDS-
To find out more, please visit www.meatandhealth.com

The Meat Advisory Panel (MAP) is a group of experts who provide independent and objective information about red meat and its role as part of a healthy, balanced diet.
MAP is supported by an unrestricted educational grant from the AHDB Pork, AHDB Beef & Lamb. AHDB Pork and AHDB Beef & Lamb are divisions of the Agriculture and Horticulture Development Board (AHDB).

For more information about the role of red meat and a selection of versatile recipes using pork, beef and lamb visit www.meatmatters.com

For more information please contact:
Nicky Smith,
nicky.smith@nexuspr.com 0207 052 8850


 

Tuesday, October 20, 2015

DOES RED MEAT CAUSE CANCER? (Mr Roger Leicester)

With so much focus once again on red meat and cancer, it’s time to dust off SACN’s 2010 Iron and Health report [1] and put things back into perspective.

An exhaustive review of the literature in 2010 by the government’s Scientific Advisory Committee on Nutrition (SACN)[2]  concluded that eating up to 70g of red meat daily does not pose a risk for colorectal cancer. SACN noted difficulties in interpreting the inconsistent evidence base saying: “it is not possible to quantify the amount of red and processed meat that may be associated with increased colorectal cancer risk because of limitations and inconsistencies in the data”.

In fact there is no evidence showing that lean, red meat has any causal relationship with the initiation of cancers.

Avoiding red meat in the diet is not a protective strategy against cancer.  Results from many studies show a very weak association between high red meat consumption and increased risk of cancer.  These include the large EPIC study, of which there is a British cohort, has found similar rates of bowel / colorectal cancer in vegetarians and meat-eaters [3].  Other studies have also shown no association between red meat intake and risk of other types of cancer including prostate [4], and breast cancer [5].

Many studies have attempted to show a link between red meat consumption and cancer but many are poorly designed, using food frequency questionnaires and lacking the use of urinary biomarkers as indicators of red meat intakes.  In fact, the interdependency of food consumption with other dietary and lifestyle factors, socioeconomic characteristics, clinical variables, and genetic traits makes it difficult to isolate the independent effects of a specific food or food group, such as meat intake, on disease risk.

Cancer specialist, Professor Karol Sikora has noted that those people who enjoy eating red meat should continue to do so; he adds: "We have created a nightmare situation of confusing messages based on very little evidence. Eating red meat in the context of a balanced diet should really not be viewed as a problem. Yes, avoid a high calorie, high fat diet - but by all means enjoy that steak.”

Follow the SACN guidance
Instead of the knee jerk reaction of eating less red meat, we have excellent guidance from SACN which advises that people who eat more than 90g red meat daily should lower their intakes to an average of 70g. Given changes to meat consumption over the past decade, average intakes are now 71g suggesting that most people don’t need to change their meat consumption.



References
[2] SACN (Scientific Advisory Committee on Nutrition) (2011). Iron and Health. http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf
[3] Keys T et al. (2014) Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr 100(suppl): 378S–85S.
[4] Rohrmann, S., et al. (2015). "Intake of meat mutagens and risk of prostate cancer in a cohort of U.S. health professionals." Cancer Epidemiol Biomarkers Prev.   
[5] Alexander, D et al (2010)” A review and meta-analysis of red and processed meat consumption and breast cancer.” Nutr Res Rev 23(2): 349-365

Friday, October 16, 2015

NITRATES, NITRITES AND BOWEL CANCER - (Professor Robert Pickard)

Much of the advice about red meat in the diet refers to unprocessed lean red meat but what about processed meat? Can we still eat it? And what’s the deal with nitrates and nitrites?

Let’s look at processed meat first. Processed meat is defined [1] as “meat preserved by smoking, curing, salting, or the addition of preservatives. This includes, for instance, ham, bacon, salami, and some sausages such as frankfurters.” Processed meat differs from fresh meat as it tends to be higher in salt and can contain preservatives added during the curing process which slow down the meat spoilage and reduce microbiological risks. You simply can’t make bacon and salami without them.

So what about nitrates and nitrites? 80% of dietary nitrates come from vegetable consumption and there is evidence that some sources of these in the diet support normal blood pressure [2].  Nitrites and nitrates are used to preserve cured meats – you can’t preserve the meat without them. Salt has also been used to preserve meat for generations.

The prime reason to use such additives is the need to protect us against the microbe Clostridium botulinum.  This bacterium produces a virulent toxin and the risk of death from botulinum is a very real public health issue.  Recent research has also documented that nitrite used in processed meat products significantly reduces growth of Listeria monocytogenes.

There are theories, mainly based on animal studies, that overcooking meat, or changes in meat due to preservation, could explain links with bowel cancer but there is no consensus on this.  In fact, an exhaustive review of the literature in 2010 by the government’s Scientific Advisory Committee on Nutrition (SACN) [3] concluded that eating up to 70g of red meat daily was consistent with normal health and adequate iron status. SACN noted difficulties in interpreting the inconsistent evidence base saying: “it is not possible to quantify the amount of red and processed meat that may be associated with increased colorectal cancer risk because of limitations and inconsistencies in the data.”

In fact, if you were going to prevent bowel cancer, the strongest evidence is for tackling smoking, alcohol, obesity and physical inactivity.


References
[2] Hord NG et al. (2009) Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr 90: 1-10.
[3]SACN (Scientific Advisory Committee on Nutrition) (2011). Iron and Health. http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf

ARE VEGETARIAN DIETS REALLY BETTER FOR HEALTH? (Dr Emma Derbyshire)

It’s perfectly possible to eat healthily on a vegetarian or vegan diet, followed by 2-4% of the population, but this requires good planning and cooking skills as well as access to alternative sources of animal-based nutrients.

Studies show that vegetarian diets can be low in zinc, calcium, iron, manganese, selenium, and copper [1]  while vegetarians and vegans often have lower intakes of vitamin D [2, 3], and long-chain omega-3 fatty acids [4]. Vitamin B12, which is required for healthy nerves and red blood cells, can be a major issue for vegans as this nutrient is only present in foods of animal or microbiological origin [5].

Vegetarians tend to be healthier than the rest of the population thanks to the combined effect of lower body mass index, more exercise, lower smoking prevalence and higher intakes of fruit, vegetables and fibre. Meat eaters can also achieve optimal health by choosing lean cuts of red meat and aiming for at least 5-a-day fruit and vegetables, as well as whole grain foods, low fat dairy products, and oily fish once a week.

As studies show that lean red meat performs just as well as carbohydrate or other protein sources in terms of blood pressure [6], body fat [7,8], glucose levels [9], and blood lipids [10],  you can still enjoy red meat during your health kick.











References
[1] Freeland-Grave-J (1988) Mineral adequacy of vegetarian diets. The American Journal of Clinical Nutrition  48:859-62
[2] Calvo Ms, Whiting SJ, Barton CN (2005) Vitamin D intake: a global perspective of current status. Journal of Nutrition 135 310-6
[3] Laskowska-Kilta T, Chelchowska M, Ambroszkiewicz J, Gajewska J, Klemarczyk W (2011) The effect of vegetarian diet on selected essential nutrients in children 15:318-25
[4] Welch AA, Shakya-Shrestha S, Lentjes MA, Wareham NJ, Khaw KT (2010) Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the product-precursor ratio [corrected] of a-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. The American Journal of Clinical Nutrition (2:1040-51
[5] Ambroszkiewicz J, Klemarczyk W, Chelchowska M, Gajewska J, Laskowska-Klita T (2006) Serum homocysteine, folate, vitamin B12 and total antioxidant status in vegetarian children. Advances in medical science 51:265-8
[6] Hodgson JM et al. (2006) Partial substitution of carbohydrate intake with protein intake from lean red meat lowers blood pressure in hypertensive persons. Am J Clin Nutr 83: 780-7.
[7] Noakes M et al. (2005) Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 81: 1298-306.
[8] Noakes M et al. (2005) Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 81: 1298-306.
[9] Turner KM et al. (2015) Red meat, dairy, and insulin sensitivity: a randomized crossover intervention study. Am J Clin Nutr 101: 1173-9.
[10] Davidson MH et al. (1999) Comparison of the effects of lean red meat vs lean white meat on serum lipid levels among free-living persons with hypercholesterolemia: a long-term, randomized clinical trial. Arch Intern Med 159: 1331-8.

HOW MUCH PROTEIN DO WE NEED? (Dr Carrie Ruxton)

I’ve been working out a lot this year in order to take part in the 105 mile Coast to Coast challenge; a two day event in September involving running, cycling and kayaking across Scotland. It was hard but I recovered well thanks to a good amount of high quality protein in my diet.
We are often told that we eat too much protein in developed countries but this really depends on your age and how much exercise you do. Yes, average intakes are above general recommendations of around 55g per day but two groups in particular need more than that; elderly folk and people taking part in regular exercise.

Studies show that, once we hit 50 years of age, our muscle mass begins to decline. This increases the risk of sarcopenia which, in later life, causes muscle wasting and may exacerbate falls. High quality protein, such as that found in red meat, helps to maintain muscle size and strength particularly when combined with resistance training[1] .

In fact, the evidence for protein’s important role in muscle function is so compelling it has been recognised by European regulators. These watchdogs have rejected hundreds of health claims but have given the approval to the statement that protein “contributes to a growth in muscle mass”.

Any food or drink which provides at least 12% of its energy from protein — as almost all red meat does [2]  — is authorised to include this important health message on packaging and marketing materials. Some cuts, such as lean rump (18%) or pork chops (20%) contain an even higher percentage of energy in the form of protein [3].

Fitness fans can also benefit from slightly more protein, especially after training sessions to help support muscle recovery. In my new review in Complete Nutrition [4] , I discuss international protein recommendations for sports enthusiasts and explain how high protein foods, such as red meat, contribute to optimal performance.






References
[1] Goisser et al. (2015) Sarcopenic obesity and complex interventions with nutrition and exercise in community-dwelling older persons--a narrative review. Clin Interv Aging 10: 1267-82.
[2] http://meatandhealth.redmeatinfo.com/media/old/Red%20meat%20and%20protein.pdf
[3]
http://meatandhealth.redmeatinfo.com/media/old/Red%20meat%20and%20protein.pdf 

Calculation for rump example: 100 divided by 176 (cals) multiplied by 31.2 (protein per 100g) equals 17.7, rounded up to 18%
[4] Ruxton C & Cobb R (2015) Benefits of protein for sport and exercise. Complete Nutrition in press.
 
 
 


COLORECTAL CANCER – THE FACTS (MR ROGER LEICESTER)

Bowel cancer is now the third most common cancer in the UK but our cancer screening methods have really moved on and as a result we are able to diagnose many more cases than ever before.

The much repeated view from meat-free campaigns and animal charities is to eat less red meat but the evidence doesn’t stack up. In fact there is no evidence showing that lean, red meat has any causal relationship with the initiation of cancers.

Avoiding red meat in the diet is not a protective strategy against cancer.  Results from many studies show a very weak association between high red meat consumption and increased risk of cancer.  These include the large EPIC study, of which there is a British cohort, has found similar rates of bowel / colorectal cancer in vegetarians and meat-eaters [1].  Other studies have also shown no association between red meat intake and risk of other types of cancer including prostate [2], and breast cancer [3].  

In fact, Bowel Cancer UK states the main risks for bowel cancer as age, gender and family history than diet and lifestyle [4].
Keeping healthy is vital and as a result I advice patients the following:
• Eat at least 5 portions of fruit and vegetables daily if not more
• Take regular exercise – half an hour a day is a good starting point as per WHO guidelines
• Aim for an average of 70g cooked red meat daily as per SACN guidelines
• Eat plenty of high fibre and wholegrain foods.






References
[1] Keys T et al. (2014) Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr 100(suppl): 378S–85S.
[2] Rohrmann, S., et al. (2015). "Intake of meat mutagens and risk of prostate cancer in a cohort of U.S. health professionals." Cancer Epidemiol Biomarkers Prev.   
[3] Alexander, D et al (2010)” A review and meta-analysis of red and processed meat consumption and breast cancer.” Nutr Res Rev 23(2): 349-365
[4] www.bowelcanceruk.org.uk/understanding-bowel-cancer/risk-factors/

DON’T FORGET ABOUT IRON (Dr Carrie Ruxton)

Last year I felt tired and lethargic and struggled to catch my breath when I climbed the stairs. I was amazed on giving my usual blood donation to discover that I was iron deficient, particularly as I eat red meat. A few months later, everything was back to normal thanks to more focus on my diet. But, it made me more aware about iron deficiency which remarkably affects one in ten women in the UK.

Everyone thinks of Popeye and spinach in relation to iron but red meat is, in fact, the best available dietary source. The haem iron in red meat is two to six times better absorbed than the non-haem iron found in pulses, green vegetables and fortified foods. Haem iron also boosts the absorption of non-haem iron making it a good idea to serve a large portion of broccoli with your steak!

Those at particular risk of low iron intakes and poor iron status are women, teenagers, athletes and people who avoid or eat very little red meat. A few dietary considerations can make all the difference such as eating red meat 4-5 times a week (up to 500g cooked weight per week), drinking a glass of orange juice with meat meals, serving green leafy vegetables with main meals, and eating fortified breakfast cereals.